Abstract

Simple patterns consisting of three spots (V and Γ) have been recognized by dividing, shifting, and recombining
beams onto bistable ZnS interference filters. This experiment demonstrates AND-gate operation,
cascading, and a moderate amount of parallelism, but a laser power of several watts was required and the
response times were several milliseconds. An associative memory for fingerprint identification has been
constructed using a VanderLugt correlator and an interference filter as a reflective thresholding device.